import sys
input = sys.stdin.readline


def print_ans(X):
    """Test Case
    >>> print_ans(30)
    Yes
    >>> print_ans(25)
    No
    >>> print_ans(35)
    Yes
    >>> print_ans(-10)
    No
    """
    if X >= 30:
        print('Yes')
    else:
        print('No')


if __name__ == '__main__':
    X = int(input().rstrip())
    print_ans(X) import sys sys input = sys.stdin.readline input sys.stdin.readline sys.stdin sys stdin readline def print_ans(X):
    """Test Case
    >>> print_ans(30)
    Yes
    >>> print_ans(25)
    No
    >>> print_ans(35)
    Yes
    >>> print_ans(-10)
    No
    """
    if X >= 30:
        print('Yes')
    else:
        print('No') print_ans """Test Case
    >>> print_ans(30)
    Yes
    >>> print_ans(25)
    No
    >>> print_ans(35)
    Yes
    >>> print_ans(-10)
    No
    """ if X >= 30:
        print('Yes')
    else:
        print('No') X >= 30 X 30 print('Yes') print 'Yes' print('No') print 'No' X X if __name__ == '__main__':
    X = int(input().rstrip())
    print_ans(X) __name__ == '__main__' __name__ '__main__' X = int(input().rstrip()) X int(input().rstrip()) int input().rstrip() ().rstrip () input rstrip print_ans(X) print_ans X input = sys.stdin.readline sys.stdin.readline input def print_ans(X):
    """Test Case
    >>> print_ans(30)
    Yes
    >>> print_ans(25)
    No
    >>> print_ans(35)
    Yes
    >>> print_ans(-10)
    No
    """
    if X >= 30:
        print('Yes')
    else:
        print('No') def print_ans(X):
    """Test Case
    >>> print_ans(30)
    Yes
    >>> print_ans(25)
    No
    >>> print_ans(35)
    Yes
    >>> print_ans(-10)
    No
    """
    if X >= 30:
        print('Yes')
    else:
        print('No') print_ans X = int(input().rstrip()) int(input().rstrip()) X
import sys
input = sys.stdin.readline


def print_ans(X):
    """Test Case
    >>> print_ans(30)
    Yes
    >>> print_ans(25)
    No
    >>> print_ans(35)
    Yes
    >>> print_ans(-10)
    No
    """
    if X >= 30:
        print('Yes')
    else:
        print('No')


if __name__ == '__main__':
    X = int(input().rstrip())
    print_ans(X)
